JP4997834B2 - microscope - Google Patents

Abstract

Provided is a microscope for focusing by inserting a split prism (5) at a focusing support time. The image of an iris stop (30) is branched into such two images by the angle deflecting action of the split prism (5) as are individually shifted and focused at symmetric positions across the optical axis of the microscope. These two branched images of the iris stop (30) are further focused on an objective lens (23) through a beam splitter (22) by the focusing action of a lens (21). The operation unit of a vertical motion device is operated to move an optical system up and down so that the images of a focused pattern (15) are viewed to move in opposite directions from each other in the field of view. At the focusing time when the focal position of the objective lens (23) is focused on a sample face (24), the images of the focused pattern (15) look in the registered state. Thus, the focusing action can be made highly precise without being restricted by the magnification or NA of the objective lens.

Description

  The present invention relates to a microscope provided with a focusing support device for focusing on an object surface of an object to be measured visually during microscope observation.

  In general, when an object surface image of an object to be measured is visually observed in a microscope (for example, when an object surface image formed on a focusing screen by an objective lens is observed through an eyepiece lens), the object surface of the object lens is If it is within the focal depth, even if the relative position of the object plane in the optical axis direction of the objective lens and the objective lens is changed within that range, the image of the object plane formed on the focusing screen is in focus. looks like. Therefore, when measuring the size and shape of an object to be measured in one object plane with high accuracy, and the dimension of the object to be measured in the height direction, for example, between two object surfaces shifted in the optical axis direction of the objective lens In the case of measuring the size of the lens with high accuracy, in particular, a focusing device that adjusts the relative position and matches the focal position of the objective lens with each object surface with high accuracy is required.

  Conventionally, as a microscope provided with such a focusing device, for example, a microscope disclosed in British Patent Publication GB 2076176A (Patent Document 1) is known. FIG. 1 shows a schematic configuration diagram of a microscope provided with a conventional focusing device described in Patent Document 1. In FIG. The lens 12 is configured so that the collector lens 10 and the split prism 5 have a substantially conjugate positional relationship. The split prism 5 includes a base prism 14 having a predetermined apex angle and a semicircular prism 16 having an apex angle twice that of the base prism. A focusing pattern 15 is formed on the light source side of the base prism 14. The focusing pattern is composed of at least one line, and straddles two regions to which different declination angles are given by the base prism 14 and the semicircular prism 16, respectively.

  The light emitted from the light source is limited by the aperture stop 13 to the optimum condition for focusing support, and enters the split prism 5. The aperture stop 13 is imaged on a microscope aperture stop 19 having a variable diameter by lenses 17 and 18. However, the image of the aperture stop 13 is branched into two by the declination action of the split prism 5, and each is formed shifted to a symmetrical position with the optical axis of the device interposed therebetween.

  The image of the aperture stop 13 branched into two is further formed on the objective lens 23 (strictly, the pupil of the objective lens 23) through the microscope field stop 20 and the beam splitter 22 by the imaging action of the lens 21. .

  The focusing support device is placed on a gantry of a vertical movement device (not shown). In order to adjust the relative position between the objective lens 23 and the object plane 24 in the optical axis direction, the operation of the vertical movement device is performed. By operating the unit, the entire optical system moves together in the optical axis direction. By moving the optical system up and down by operating the operation unit of the vertical movement device, it can be seen that the images of the focusing pattern move in opposite directions within the field of view, and the focal position of the objective lens 23 matches the sample surface 24. At the time of focusing, it is arranged so that the image of the focusing pattern can be seen in a matched state. Further, when the image is out of focus (for example, when the sample surface is at 24a), the image of the focused pattern appears to be shifted, and the lines of the focused pattern are projected as two lines separated by d on the sample surface 24a. Is done.

The aperture stop 13 and the split prism 5 are configured to be able to be inserted into and removed from the optical path by an unillustrated insertion / removal mechanism. When focusing is supported, the split prism 5 and the aperture stop 13 are inserted into the optical path, and are adjusted by matching the focusing pattern. I'll do it. In observation, the aperture stop 13 and the split prism 5 are removed from the optical path, thereby functioning as a normal microscope epi-illumination device.
British Patent Publication GB 2076176A

  In the focusing support apparatus described in Patent Document 1, an aperture stop 13 is conjugated with a microscope aperture stop 19 and a focusing pattern 15 is conjugated with a microscope field stop 20 by lenses 17 and 18, and intermediate images are once formed. Thereafter, they are projected onto the objective lens pupil plane and the sample plane 24, respectively. This makes it possible to modularize 12 to 18 and add functions to an ordinary microscope. On the other hand, the device configuration is complicated, which not only increases costs but also enlarges the device. Is undesirable.

  The present invention has been made in view of such circumstances, has a simpler and more compact configuration, and can be focused accurately without being limited by the magnification and NA of the objective lens. It is an object of the present invention to provide a microscope including the device.

A first means for solving the problem is a microscope that includes a focusing support device and observes a surface to be observed, and includes a light source, a first lens group, and the first lens group. and diameter varying throttle disposed in the light source and coupled to a member having a focusing indicator, the diameter-illuminated by the light beam is limited by the strange diaphragm, with respect to the optical axis and to each other inclined at a predetermined angle an optical path branching member which forms two light beams, a second lens group is constituted by the objective lens, the diameter varying diaphragm is disposed pupil conjugate of the objective lens through the second lens group, and said focusing indicator of said optical path branching member, wherein the observation target surface is disposed in a conjugate by the second lens group and the objective lens, the optical path branching member is Ri detachably der from the microscope optical path, wherein A diaphragm with a variable diameter is provided on the surface to be observed. While incident beam, said a microscope, characterized in that the narrowed diameter such that the two light beams incident on the observed surface is inclined is adapted to be adjustable.

  In this means, in Patent Document 1, the optical path branching member and its focusing index are arranged at the position where the microscope field stop 20 is placed, and the optical path branching member can be inserted and removed from the microscope optical path. Accordingly, the focus index is directly projected onto the surface to be observed without intermediate imaging, and the configuration is simpler and smaller than the conventional one.

  In this measure, instead of omitting the aperture stop used for optimizing the illumination conditions in the conventional method, the aperture of the microscope is made a variable diameter iris (iris stop) to optimize the light flux when focusing is supported. Is possible. Therefore, the configuration is simpler and more compact, and the diameter φ of the variable aperture can be set to a predetermined value suitable for focusing support, as will be described later with a specific example. It can be set as the microscope provided with the focusing assistance apparatus which can focus with sufficient precision, without being restrict | limited to the magnification and NA of a lens.

ただし、β_１は前記光源が前記第１のレンズ群により前記径可変な絞りの位置に結像する像の倍率、ａは前記光源の大きさ、φ_Ｍは前記径可変な絞りの最大径、εは前記光路分岐部材により与えられる光束の傾斜角、Ｌは前記径可変な絞りと前記合焦指標との距離、φ_０は前記対物レンズの瞳の直径、β_２は前記径可変な絞りが前記第２のレンズ群を介して前記対物レンズの瞳の位置に結像する像の倍率である。
The second means for solving the problem is the first means, and the diameter of the variable diameter diaphragm is given by satisfying the following conditional expressions (1) and (2) simultaneously: It is characterized by.

Where β ₁ is the magnification of an image formed by the light source at the position of the diaphragm with variable diameter by the first lens group, a is the size of the light source, φ _M is the maximum diameter of the diaphragm with variable diameter, ε is the tilt angle of the light beam provided by the optical path branching member, L is the distance between the variable diameter aperture and the focusing index, φ ₀ is the pupil diameter of the objective lens, and β ₂ is the variable diameter aperture. It is a magnification of an image formed at the position of the pupil of the objective lens through the second lens group.

  In this means, as will be described later, the phenomenon that the diameter φ of the variable diameter stop is too small and the illumination light does not reach the object surface does not occur, and the diameter φ of the variable diameter stop is too large. The function as a focus support device is not lost. Therefore, it can be set to be suitable for focusing support.

ただし、β_１は前記光源が前記第１のレンズ群により前記径可変な絞りの位置に結像する像の倍率、ａは前記光源の大きさ、φ_Ｍは前記径可変な絞りの最大径、εは前記光路分岐部材により与えられる光束の傾斜角、Ｌは前記径可変な絞りと前記合焦指標との距離、φ_０は前記対物レンズの瞳の直径、β_２は前記径可変な絞りが前記第２のレンズ群を介して前記対物レンズの瞳の位置に結像する像の倍率である。
A third means for solving the above-described problem is a microscope that includes a focusing support device and observes a surface to be observed, and includes a light source, a first lens group, and the first lens group. A member having a variable-diameter stop arranged in conjugate with the light source and a focusing index, illuminated with a light beam limited by the variable-diameter stop, and tilted at a predetermined angle with respect to the optical axis An optical path branching member that forms two light beams, a second lens group, and an objective lens, and the aperture having a variable diameter is arranged conjugate with the pupil of the objective lens via the second lens group, And the focusing index of the optical path branching member and the surface to be observed are arranged in a conjugate manner by the second lens group and the objective lens, and the optical path branching member is detachable from a microscope optical path, and the optical path The branch member is formed on the surface to be observed with the two While incident beam, said a microscope, characterized in that the two light beams incident on the observed surface is configured to be able to set the polarization angle of the optical path splitting member so as to be inclined.
A fourth means for solving the problem is the third means, and the deflection angle of the optical path branching member satisfies the following conditional expressions (3), (4), and (5) simultaneously: It is characterized by being given by.

Where β ₁ is the magnification of an image formed by the light source at the position of the diaphragm with variable diameter by the first lens group, a is the size of the light source, φ _M is the maximum diameter of the diaphragm with variable diameter, ε is the tilt angle of the light beam provided by the optical path branching member, L is the distance between the variable diameter aperture and the focusing index, φ ₀ is the pupil diameter of the objective lens, and β ₂ is the variable diameter aperture. It is a magnification of an image formed at the position of the pupil of the objective lens through the second lens group.

  In this means, as will be described later, the phenomenon that the illumination light does not reach the object surface due to the inclination angle ε of the light beam provided by the optical path branching member does not occur, and the light beam provided by the optical path branching member does not occur. The tilt angle ε is too small to stop functioning as a focusing support device. Therefore, it can be set to be suitable for focusing support.

A fifth means for solving the above-mentioned problem is the second means, which satisfies the following conditional expression (6).

  In this means, as will be described later, even when an objective lens having a different pupil diameter is switched and used, good focusing support is always possible without depending on the pupil diameter of the objective lens.

A sixth means for solving the above-mentioned problem is the fourth means, which satisfies the following conditional expression (7).

  In this means, as will be described later, even when an objective lens having a different pupil diameter is switched and used, good focusing support is always possible without depending on the pupil diameter of the objective lens.

  According to the present invention, it is possible to provide a microscope having a focusing support device that has a simpler and more compact configuration and can focus accurately without being limited by the magnification and NA of the objective lens. Can do.

  Hereinafter, a microscope provided with the focusing device according to the first embodiment of the present invention will be described with reference to FIG. The light emitted from the light source 1 is collected at the position of the iris diaphragm 30 by the collector lens 10 and the lens 12, and forms an image of the light source 1 at a magnification β1. The split prism 5 includes a base prism 14 having a predetermined apex angle and a semicircular prism 16 having an apex angle twice that of the base prism. A focusing pattern 15 is formed on the light source side of the base prism 14. The focusing pattern is composed of at least one line, and straddles two regions to which different declination angles are given by the base prism 14 and the semicircular prism 16, respectively. The split prism 5 is installed so that it can be inserted and removed from the optical path of the apparatus by an unillustrated insertion / removal mechanism.

  When the sample is observed, the split prism 5 is removed from the optical path of the apparatus, and functions as a general microscope epi-illumination apparatus. At this time, when the split prism 5 deviates from the optical path in order to limit an extra light beam of illumination, a field stop 19 is preferably inserted in place of the split prism 5.

  The diameter of the iris diaphragm 30 is configured so as to be freely set within its mechanical constraints, and is used to control the coherence factor of the illumination light. By adjusting the diameter of the iris diaphragm 30, the coherence factor is increased or decreased, and the observer can freely set the illumination conditions according to the observation target.

  On the other hand, when focusing is supported, the split prism 5 is inserted to perform focusing. The light emitted from the light source is limited in its luminous flux by the iris diaphragm 30 and enters the split prism 5. The image of the iris diaphragm 30 is imaged on the pupil EP of the objective lens 23 through the beam splitter 22 by the image forming action of the lens 21. However, the image of the iris diaphragm 30 is branched into two by the declination action of the split prism 5, and each is formed shifted to a symmetrical position across the optical axis of the apparatus. The image of the iris diaphragm 30 branched into two is further formed on the objective lens 23 (strictly, the pupil of the objective lens 23) through the beam splitter 22 by the imaging action of the lens 21.

  The focusing support device is placed on a gantry of a vertical movement device (not shown). In order to adjust the relative position between the objective lens 23 and the object plane 24 in the optical axis direction, the operation of the vertical movement device is performed. By operating the unit, the entire optical system moves together in the optical axis direction. By operating the operation unit of the vertical movement device to move the optical system up and down, it can be seen that the images of the focusing pattern 15 move in opposite directions within the field of view, and the focal position of the objective lens 23 matches the sample surface 24. At the time of focusing, they are arranged so that the image of the focusing pattern 15 can be seen in a matched state. Further, when the image is out of focus (for example, when the sample surface is at 24a), the image of the focus pattern 15 appears shifted, and the line of the focus pattern 15 is two lines separated by d on the sample surface 24a. As projected.

  Here, with reference to FIG. 3 and FIG. 4, the optimal setting at the time of focusing assistance is demonstrated. FIGS. 3 and 4 both show the spread of the light beam on the objective lens pupil plane EP. FIG. 3 shows a case where the expression (1) is satisfied, and the maximum diameter of the iris diaphragm 30 is smaller than that of the image of the light source 1 formed at the position of the iris diaphragm 30, and the iris diaphragm 30 is opened. The case where an object is illuminated using a part of the area of the light source 1 is shown. The iris diaphragm 30 is branched into two by the declination action of the split prism 5, and images of the iris diaphragm 30 are formed on the objective lens pupil plane EP as 30a and 30b.

  FIGS. 3A to 3E show how the sizes of the images 30a and 30b are changed by adjusting the diameter of the iris diaphragm 30. FIG. Here, when the iris diameter of the iris diaphragm 30 is too small as shown in FIG. 3A, the illumination light beam does not enter the pupil of the objective lens, and the illumination light does not reach the object plane. On the other hand, as shown in FIG. 3E, when the iris diameter of the iris diaphragm 30 is too large, the light beam is projected onto the sample surface 24 without being inclined, so that the image of the reference pattern 15 changes according to the vertical movement of the apparatus. It will not move and will not function as a focusing support device. Therefore, the diameter of the iris diaphragm 30 at the time of focusing support needs to be adjusted as shown in FIGS. 3 (b) to 3 (d). Expression (2) represents this condition range. In order to set the above-described conditions, the aperture of the microscope is the iris diaphragm 30 and the light beam can be optimized by observing the objective lens pupil at the time of focusing support.

  Regarding the adjustment of the iris diaphragm 30, the dimensions, magnifications, and deflection angles of the split prism 5 are designed so as to satisfy the above-described conditions when the maximum aperture diameter of the iris diaphragm 30 is set. It is desirable to design so that the above-mentioned conditions can be satisfied only by opening.

  As a more preferable mode, an unillustrated insertion / removal mechanism for inserting / removing the split prism 5 is operated so that the diameter of the iris diaphragm 30 is forcibly set to a range satisfying the above conditions when the split prism 5 is inserted. It has been done.

  On the other hand, FIG. 4 shows a case where the expression (3) is satisfied, and the maximum diameter of the iris diaphragm 30 is larger than the image of the light source 1 imaged at the position of the iris diaphragm 30, and the iris diaphragm 30 is opened. In some cases, the object is illuminated using the entire area of the light source 1. The aperture stop 30 is bifurcated by the declination action of the split prism 5, and forms an image of the iris stop 30 on the objective lens pupil plane EP as shown by 30a, 30b. Similarly, the image of the light source 1 is formed on the pupil plane EP of the objective lens as indicated by 1a and 1b.

  FIG. 4A to FIG. 4D show how the split prism 5 changes according to the deviation angle ε. When the declination ε is too large as shown in FIG. 4A, the illumination light beam does not enter the pupil of the objective lens, and the illumination light does not reach the object plane. On the other hand, when the declination ε is too small as shown in FIG. 4E, the light beam is projected onto the sample surface 24 without being inclined, so that the image of the reference pattern 15 does not move in accordance with the vertical movement of the apparatus. As a result, the function as a focusing support device cannot be performed. Therefore, the deflection angle ε of the split prism 5 used at the time of focusing support needs to be designed as shown in FIGS. 4B to 4D. Expression (5) expresses the condition range. In addition, the iris diaphragm 30 needs to be incident on the pupil EP of the objective lens without blocking the image of the light source 1, and this condition is expressed by equation (4).

  Regarding the adjustment of the iris diaphragm 30, when setting the maximum iris diameter of the iris diaphragm, the dimensions, magnifications, and deflection angles of the split prism 5 are designed so as to satisfy the above-mentioned conditions, and the iris diaphragm is opened when focusing is supported. It is desirable to design so as to satisfy the above conditions.

  As a more preferable embodiment, an unillustrated insertion / removal mechanism for inserting / removing the split prism 5 is operated so that the diameter of the iris diaphragm 30 is forcibly set to a range satisfying the above conditions when the split prism 5 is inserted. Is to do.

  Although the microscope having the focusing support function according to the embodiment of the present invention has been described above, the microscope of the present invention is not limited to the above-described embodiment, and can be freely changed within the scope of the present invention. For example, in the above-described embodiment, the microscope optical system has been described using a schematic diagram of an infinite optical system. However, the present invention is not limited to this, and the present invention can be similarly applied to a finite optical system.

  In the present embodiment, the split prism 5 is composed of the base prism 14 and the semicircular prism 16 having an apex angle twice that of the base prism. However, the present invention is not limited to this configuration. For example, as shown in FIG. The base prism 14 may be a parallel plate 34, and two declination prisms 32 having a predetermined declination may be joined to the base prism so as to incline the light beams in opposite directions. Or you may shape | mold the said shape integrally by a plastic mold.

  Next, a microscope provided with a focusing device according to a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, suitable condition settings are shown in a microscope that switches a plurality of objective lenses. Note that the schematic configuration of the microscope including the focusing device according to the present embodiment is the same as that of the first embodiment, and a description thereof will be omitted.

  FIG. 6 shows a case where the expression (1) is satisfied, and the maximum diameter of the iris diaphragm 30 is smaller than the image of the light source 1 formed at the position of the iris diaphragm 30, and the iris diaphragm 30 is opened. The case where an object is illuminated using a part of the area of the light source 1 is shown. In general, the diameters of the pupils of the objective lens are different from each other, and tend to be smaller as the magnification is higher and larger as the magnification is lower. In the second embodiment, as shown in FIG. 6, the condition is set such that the light beam 30a and the light beam 30b just touch each other on the objective lens pupil.

By setting in this way, even when switching between objective lenses having different pupil diameters as described above, it is possible to always provide good focusing support regardless of the pupil diameter of the objective lens. Expression (6) expresses this condition range. It can be seen that conditional expression (6) is a condition that does not depend on the pupil diameter φ ₀ of the objective lens. In order to set the above conditions, the aperture of the microscope is used as an iris diaphragm, and the objective lens pupil at the time of focusing support is observed to optimize the light flux.

  On the other hand, FIG. 7 shows a case where the expression (3) is satisfied, and the maximum diameter of the iris diaphragm 30 is larger than that of the image of the light source 1 formed at the position of the iris diaphragm 30, and the iris diaphragm 30 is opened. In some cases, the object is illuminated using the entire area of the light source 1. As shown in FIG. 7, the declination angle ε of the split prism 5 used for focusing support is designed so as to satisfy the condition that the light beam 1a and the light beam 1b just touch each other on the objective lens pupil. By designing in this way, even when an objective lens having a different pupil diameter is switched and used, good focusing support can always be provided without depending on the pupil diameter of the objective lens.

Expression (7) represents this condition range. It can be seen conditional expression (7) is a condition that is independent of the pupil diameter phi ₀ clearly objective lens. In addition, the iris diaphragm 30 needs to be incident on the pupil EP of the objective lens without blocking the image of the light source 1, and this condition is expressed by equation (4).

  Regarding the adjustment of the iris diaphragm 30, preferably, the dimensions, magnifications, and deflection angles of the split prism 5 are designed so as to satisfy the above-mentioned conditions when the maximum iris diameter of the iris diaphragm is set. It is desirable to design so that the above-mentioned conditions can be satisfied only by opening.

  In a more preferred mode, an unillustrated insertion / removal mechanism for inserting / removing the split prism is operated to forcibly set the diameter of the iris diaphragm 30 in a range satisfying the above conditions when the split prism is inserted. .

It is a figure which shows the structure of the focusing operation assistance apparatus in a prior art. It is a figure which shows the structure of the focusing assistance apparatus in the 1st Embodiment of this invention. It is a figure showing the light beam on the objective-lens pupil in the 1st Embodiment of this invention. It is a figure showing the light beam on the objective-lens pupil in the 1st Embodiment of this invention. It is a figure which shows the structure of the focusing assistance apparatus in the 1st Embodiment of this invention. It is a figure showing the light beam on the objective-lens pupil in the 2nd Embodiment of this invention. It is a figure showing the light beam on the objective-lens pupil in the 2nd Embodiment of this invention.

Explanation of symbols

1: Light source, 1a, 1b: Light source image on objective lens pupil, 5: Split prism, 10: Collector lens, 12, 17, 18, 21: Lens, 13: Aperture stop, 14: Base prism, 15: Focusing Pattern: 16: Semicircular prism, 19: Microscope aperture stop, 20: Microscope field stop, 22: Beam splitter, 23: Objective lens, 24: Sample plane, 24a: Sample plane, 30: Iris stop, 30a, 30b: Objective Image of iris diaphragm on lens pupil, 31: second objective lens, 32: declination prism

Claims (6)

A microscope equipped with a focusing support device and observing the surface to be observed ,
A light source;
A first lens group;
And diameter varying throttle disposed in the light source and the conjugate through the first lens group,
A member having a focusing index, which is illuminated with a light beam limited by the diaphragm having a variable diameter , and forms two light beams that are inclined at a predetermined angle with respect to the optical axis;
A second lens group;
Consists of an objective lens,
The diameter varying diaphragm are arranged in a pupil conjugate with the objective lens through the second lens group, and said focusing indicator of said optical path branching member, wherein the observed surface and said second lens group and is disposed at a conjugate by the objective lens, the optical path branching member is Ri detachably der from the microscope optical path, the diameter varying diaphragm, said while entering the two light beams on the observed surface, the object observation plane A microscope characterized in that the diameter of the stop can be adjusted so that the two light beams incident on the lens are inclined . 2. The microscope according to claim 1 , wherein the diameter of the aperture having a variable diameter is given by simultaneously satisfying the following conditional expressions (1) and (2).

Where β ₁ is the magnification of the image formed by the light source at the aperture position with the variable diameter by the first lens group, a is the size of the light source, and φ _M is the maximum diameter of the variable aperture. , Ε is the tilt angle of the light beam provided by the optical path branching member, L is the distance between the variable diameter aperture and the focusing index, φ ₀ is the diameter of the pupil of the objective lens, β ₂ is the variable diameter aperture Is the magnification of an image formed at the pupil position of the objective lens via the second lens group. A microscope equipped with a focusing support device and observing the surface to be observed ,
A light source;
A first lens group;
A variable-diameter stop disposed conjugate with the light source via the first lens group;
A member having a focusing index, which is illuminated with a light beam limited by the diaphragm having a variable diameter , and forms two light beams that are inclined at a predetermined angle with respect to the optical axis;
A second lens group;
Consists of an objective lens,
The aperture having a variable diameter is disposed in a conjugate manner with the pupil of the objective lens via the second lens group, and the focusing index of the optical path branching member and the surface to be observed are the second lens group. and is disposed at a conjugate by the objective lens, the optical path branching member is Ri detachably der from the microscope optical path, the optical path branching member, said while entering the two light beams on the observed surface, the observation target surface A microscope characterized in that the deviation angle of the optical path branching member can be set so that the two incident light beams are inclined . 4. The microscope according to claim 3 , wherein the deflection angle of the optical path branching member is given by simultaneously satisfying the following conditional expressions (3), (4), and (5).

Where β ₁ is the magnification of the image formed by the light source at the aperture position with the variable diameter by the first lens group, a is the size of the light source, and φ _M is the maximum diameter of the variable aperture. , Ε is the tilt angle of the light beam provided by the optical path branching member, L is the distance between the variable diameter aperture and the focusing index, φ ₀ is the diameter of the pupil of the objective lens, β ₂ is the variable diameter aperture Is the magnification of an image formed at the pupil position of the objective lens via the second lens group. The microscope according to claim 2 , wherein the following conditional expression (6) is satisfied.

The microscope according to claim 4, wherein the following conditional expression (7) is satisfied.

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